1. Field of the Invention
Embodiments of the present invention relate to systems and methods for using eyeball surface topography as a biometric discriminator. More particularly, embodiments of the present invention relate to systems and methods for using the exterior surfaces of the cornea or sclera as a biometric discriminator and a gaze tracking system to initially and continuously verify the identity of a user using these exterior surfaces.
2. Background of the Invention
Biological processes are not deterministic. Although most people have ten fingers and ten toes, the ridges and groves that populate the surface of these digits are unique to the individual. Since fingerprints are probably the most commonly known biometric, other biometrics are often referred to as biometric fingerprints. Other measures, such as the lengths of the fingers and toes, have been proposed as biometric discriminators. The list of unique patterns that have been used or proposed as biometrics is vast, from the ridges of the ears to the blood vessels on the retinas to the bite pattern of the teeth to the features of the irises.
The term biometric has evolved in the prior art. In U.S. Pat. No. 6,601,956 the term is used to indicate just the measurement of the biological system. More recently the term has been used to include the concept of biometric discrimination; that is the ability to differentiate one person from some or all other persons. Unless otherwise noted, this second meaning of the term is used herein.
DNA is considered the “gold standard” of biometric differentiation, but is invasive and time consuming, making it a poor choice for personal identification for such applications as building access or ATM (automatic teller machine) use. Finger prints are generally believed to differentiate one person from all others. However, like most biometric discriminators, the size and quality of the sample yield the degree of separation. For full differentiation, a 10-point fingerprint match is required; that is 10 features within the fingerprint pattern must match the exemplar. A partial fingerprint with only 5 matching features might only exclude 80% of the population from the matching group. Such weak differentiation can only be used for very casual security or it must be paired with other biometric discriminator to effectively provide positive identification.
Iris recognition and retinal scans have similar limitations. The quality of the sample, the discernable features and the distribution of the population are all factors in the likelihood that the biometric sample can differentiate between an individual and the rest of the population.
In view of the foregoing, it can be appreciated that a substantial need exists for systems and methods that can advantageously improve the quality of the sample and increase the number of discernable features in biometric discrimination systems.